Reaction Kinetics Mechanisms and Catalysis
·
2024
·Vol. 137
·期 3
·1701-1720
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IF 1.7
Guo Kailiang,Liu Shuang,Men Yong,Li Lin,Hu Jiajia,Xu Junzhe,Sun Chenghui,Wei Gaixia,Wang Jinguo,He Shan,Wu Bin,Huang Xiaohui
Herein, we prepared Pd nanoparticle (NP) catalysts using XC-72 carbon supports through a tailored deposition–precipitation method. Our primary objective was to unravel the size effects of Pd NPs on hydrogenation of tetraacetyldibenzylhexaazaisowurtzitane (TADBIW), a pivotal intermediate for synthesis of high energy density materials hexanitrohexaazaisowurtzitane (CL-20). The controlled modulation of Pd NP size ranged from a mere 1.8 nm to 7.4 nm. Remarkably, our investigations into TADBIW hydrogenation unveiled a fascinating trend: the ultrasmall-sized Pd NPs with a diameter of 1.8 nm exhibited excellent yield and reaction rates. In stark contrast, their larger-sized counterparts demonstrated diminished catalytic activities. To disclose the size-dependent nature, various characterization techniques were employed, including XRD, TEM, XPS, CO and H 2 pulse chemisorption. The comprehensive analysis revealed that the ultrasmall-sized Pd possessed more positively charged sites and exhibited higher dispersion. This unique configuration facilitated an accelerated adsorption of hydrogen and the electron-rich substrate TADBIW. Notably, this phenomenon led to a reduction in the activation energy through a thermodynamic effect, thereby enhancing overall catalytic performance. Our results strongly suggested that the ultrasmall-sized Pd NPs can exert a dominated influence on the physical and chemical states of the active sites, playing a key role in triggering the adsorption and activation of the substrate TADBIW. These findings not only deepen our understanding of the intricate connections between Pd NP size and catalytic activity but also open new avenues for advancing the design and optimization of catalysts in the hydrodebenzylation methodologies and synthesis of related compounds.
研究领域:
材料科学
·
催化化学
·
能源材料
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2025
·
IF 3.9
Bin Zhang,Xiaodong Guo,Xin Feng,Xiaoxia Duan,Guilong Wang,Chao Yang
The debenzylation reaction of hexabenzylhexaazaisowurtzitane (HBIW) and 2,6,8,12-tetraacetyl-4,10-dibenzyl-2,4,6,8,10,12-hexaazaisowurtzitane (TADBIW) to synthesize 2,6,8,12-tetraacetyl-2,4,6,8,10,12-hexaazaisowurtzitane (TAIW) is the major challenge in the production of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (HNIW). This is primarily attributed to the reaction needing a lot of palladium catalysts, which tend to deactivate rapidly during the process. In this work, a series of Pd(OH)2/C catalysts were successfully prepared through a convenient deposition-precipitation method by controlling the flow rate of the PdCl2 solution. Employing the 10% Pd(OH)2/C–F0.5 sample, the debenzylation reaction was successfully completed with a lower usage of Pd and shorter time of reaction. For the HBIW debenzylation reaction, the yield of TADBIW was 87.4% at low temperature (25 °C) when 1‰ Pd/HBIW was used, and the higher yield was 89.8% at high temperature (45 °C) when 3‰ Pd/HBIW was used. The TADBIW/Pd/h values of them were 42.5 and 95.7, respectively. For the TADBIW debenzylation reaction, the complete conversion of the reactant was realized when Pd/TADBIW was 2‰. The value of TAIW/Pd/h was 154.6 when Pd/TADBIW was 4‰, which was higher than the reports. Compared to the reported catalysts, the dosage of Pd used in the debenzylation reactions of HBIW and TADBIW was significantly decreased. Furthermore, the 10% Pd(OH)2/C–F0.5 sample was recycled six times with similar performance, demonstrating excellent stability. Based on the analysis of characterization results, it is effortless to find that the flow rate of the PdCl2 solution plays a key role in controlling the adsorption behavior of palladium species on activated carbon. The lower flow rate is beneficial to obtaining Pd nanoparticles with a smaller size, a higher proportion of Pd2+, and a higher metal distribution. This study may provide a simple way to develop palladium catalysts with high performance for related applications.
研究领域:
化学工程
·
催化材料科学
✓ 已验证
产品关联
DOI
高影响因子
ORGANIC PROCESS RESEARCH & DEVELOPMENT
·
2014
·
IF 2.549
Kai Dong,Cheng H. Sun,Jian W. Song,Gai X. Wei,Si P. Pang
Synthesis of 2,6,8,12-tetraacetyl-2,4,6,8,10,12-hexaazaisowurtzitane (TAIW) by catalytic hydrogenolysis of 2,6,8,12-tetraacetyl-4,10-dibenzyl-2,4,6,8,10,12-hexaazaisowurtzitane (TADBIW), a key step for the synthesis of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (HNIW), has been first implemented under continuous flow conditions using the commercially available H-Cube Pro reactor. Several variables (i.e., reaction temperature, flow rate, and pressure) and the stability of the system have been investigated to optimize the operating conditions. The results show that a continuous flow system provides a better yield than a batch system. For instance, the yield is 99% at the optimized conditions, while the best yield from batch reactions is 92%. Continuous flow synthesis of TAIW has potential applications in improving the production technologies of HNIW for its many advantages over batch reactions.
研究领域:
化学合成
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）